1. Field of the Invention
The present invention relates to a temperature measuring method using a radiation thermometer for measuring the temperature of a measuring object, such as a semiconductor wafer, and capable of calibrating the radiation thermometer before temperature measurement.
2. Description of the Related Art
Semiconductor device manufacturing methods include various heat treatment process, such as an annealing process for annealing a semiconductor wafer after a predetermined impurity has been added to the wafer by a doping process, and various thermal processes, such as film forming processes and etching processes. Since the temperature of the wafer is a significant parameter of the heat treatment process and the thermal process, the control of the temperature of the semiconductor wafer is very important.
A reference value of the result of processing for each recipe, i.e. a value of the result of processing possibly accurately reflecting the effect of the temperature prescribed by each recipe is determined. The reference value of the result of processing for each recipe may be the result obtained when the process is carried out according to the recipe while the temperature of the measuring object is measured by the radiation thermometer calibrated on the basis of temperatures measured by a thermocouple attached to the measuring object.
A radiation thermometer is used for the measurement of the temperature of a semiconductor wafer in a relatively high temperature range. The radiation thermometer measures the intensity of the thermal radiation of a measuring object and determines a temperature on the basis of the measured intensity of the thermal radiation. The emissivity of the semiconductor wafer is dependent on the surface roughness of the semiconductor wafer and the thickness of a film formed on the surface of the semiconductor wafer. Therefore, the temperature of the semiconductor wafer cannot accurately be measured by the radiation thermometer.